There are a multitude of variants to provide pilots and operators with a visual indication of the attitude of an aircraft in space.
In particular, there are two major concepts, namely the moving-horizon/fixed-aircraft taking aircraft coordinates as a reference system and the moving-aircraft/fixed-horizon display referencing to earth coordinates. They are referred to as egocentric (inside-out) and exocentric (outside-in) indicator.
Both variants may be provided on head-down traditional instruments, on multifunction displays, on a head-up display and on head-mounted displays.
An egocentric attitude indicator uses the aircraft as the orientational viewpoint, such that the display reflects the way the visual environment might appear to the pilot inside the cockpit looking out as the horizon moves across the windscreen. When the aircraft banks (or rolls), for example, the display horizon tilts in the opposite direction against a fixed aircraft symbol. When placed along the longitudinal axis of the air-craft, this view is conformal with the real horizon.
For an exocentric attitude indicator, the viewpoint is that of an observer outside the aircraft who looks at a moving aircraft with respect to a fixed horizon. Therefore, when the aircraft banks, the horizon line remains stationary and the aircraft symbol tilts in accordance with the control input.
The standard attitude indicator in Russian aircraft is exocentric, as well as in some older Western aircraft. Usually, Russian aircraft display only bank in an exocentric manner while pitch is displayed outside-in. All exocentric displays feature an aircraft symbol which rotates in accordance with the bank angle (or roll angle). By contrast, most Western-built aircraft use egocentric attitude indicators.
Further interesting information for a pilot or an operator is the angle of attack based on the difference between the pitch of the aircraft and the flight path of the aircraft. Angle of attack indicators are typically standard round-dial instruments presenting either the angle of attack directly or as the ratio of the angle of attack versus a reference angle of attack.